In the related art, an attempt has been made to develop a flat electron emission apparatus having an array of electron emission sources formed of cold cathodes, which does not require heating of the cathodes. Examples include a FED using a Spindt cold cathode as an electron emitting portion of a display device. The light-emitting principle thereof is the same as a CRT (cathode ray tube), and light rays are emitted by leading electrons into vacuum environment by a gate electrode located apart from the cold cathode to cause the electrons to collide with fluorescent material applied on a transparent anode (see Patent Documents 1 to 3 listed below).
On the other hand, the electron emission source of this type has a problem such that the manufacturing process of a minute Spindt cold cathode is complicated and a large number of processes are required, and therefore a process yield is low.
There is also a flat electron emission apparatus in which an electron emission device having a metal-insulator-semiconductor (MIS) structure or a metal-insulator-metal (MIM) structure is used. For example, there is an electron emission apparatus disclosed in Patent Document 4 by the applicant of the present invention listed below.
In general, the MIM or MIS electron emission device having an insulator layer as thick as several tens nm to several mm can hardly achieve electron emission only by manufacturing the device. Therefore, so-called “forming process” is required. The forming process is very low in controllability, and hence it is difficult to manufacture the device stably with desirable reproducibility.
As another type of the electron emission device, there is also a surface conducting electron emission device having an electron emitting portion formed of a crack in a conductive thin film provided by forming the conductive thin film between opposed electrodes provided on an insulating substrate and supplying electricity. The crack is formed by locally disrupting, transforming or deforming the conductive thin film, whereby there are problems such that the uniformity of the interior of the electron emitting portion and reproducibility of the initial performance are insufficient. In order to solve such problems, various attempts have been made to improve the electron emission apparatus (see Patent Documents 5 to 8 listed below).    Patent Document 1: JP-A 2003-141983    Patent Document 2: JP-A 08-171877    Patent Document 3: JP-A 07-029520    Patent Document 4: U.S. Pat. No. 6,285,123    Patent Document 5: JP-A 2000-251677    Patent Document 6: JP-A 2000-251688    Patent Document 7: JP-A 2000-82388    Patent Document 8: JP-A 09-199006